Electromagnetic relay



Nov. 17, 1964 B. s. LoMAN ELECTROMAGNETIC RELAY Filed May 9, 1961 FIG. 1

FIG. 2

v it Y Y,

i United States Patent O "ice 3,157,764 ELECTRMAGNETIC RELAY Berend S.Loman, Almelo, Netherlands, assigner to Texas Instruments Incorporated,Dallas, Tex., a corporation of Delaware Filed May 9, 1961, Ser. No.108,903 ll Claims. (Cl. Zim-87) This invention relates to anelectromagnetic relay.

Many electromag .etic relays of the kind employed as motor-startingrelays often have the disadvantage that their operation is entirelydependent upon the position in which the relay is mounted. Moreover,such relays are often not sutliciently precisely adjustable with respectto the current values at which actuation of the relay contact-s willtake place and also the sensitivity cannot always be easily adjusted.

Accordingly among the several objects of the invention is the provisionof an improved construction of an electromagnetic relay, which obviatesor at least minimizes the above-rnentioned disadvantages.

Other objects will be in part apparent and in part pointed outhereinafter.

Briefly according to the invention the relay is provided with arotatable armature, which in the nonenergized state is subject to thetension of a spring acting thereon biasing the armature into anon-aligned position with respect to the poles of the electromagnet.

A part of the shaft or spindle which mounts the armature for rotation isprovided with a portion of substantially rectangular cross-section whichis engaged on opposite sides thereof by the legs `of a U-shapedleafspring extending perpendicularly to the axis of rotation of thearmature. Each of the legs of the spring carry, at their free endsextending past the armature shaft, a movable electrical contact. Theoperation of the relay according to the present invention is whollyindependent of the position in which is is mounted.

The present invention also provides means for adjusting the sensitivityof the relay with precision, which means includes a coil spring having aportion extending perpendicularly to and fastened at its inner end toone of the ends of the armature shaft, with the outer end of the springfastened to a coaxial adjusting screw adjacent the periphery thereof,which screw is threaded into the frame of the relay.

The invention will now be further described with reference to thedrawing, in which there is represented one embodiment of anelectromagnetic relay according to the invention, in which:

FEGURE l shows a section of the relay along the plane determined by theaxis of the electromagnet and the axis of the rotatable relay armaturewhich extends perpendicular thereto; and

FGURE 2 represents a section along plane Ii-ll of HGURE l.

The represented relay is disposed in a housing which consists of a coveror cap 1 and a base 2 form fitting therein, and which has at each endthereof an opstanding part 3 extending perpendicular to base 2, and bywhich the base 2 is guided into oriented position within the cover orcap l.

Disposed within the cover or cap i is an electromagnet which consists ofa coil d and a core 5, on whose ends there are fastened lamellarpole-pieces o, which, when 3,157,7@4 Patented Nov. 17, 1964 the housingis closed, extend along and are maintained in position by the inner sideof the upstanding parts 3 of the base.

Between the free ends of the pole pieces 6 there is positioned anarmature 7, formed of a bar or strip of mild steel which is rotatableabout an axle or shaft 8 extending perpendicular Ito the axis of thecore 5, with the ends of the shaft 3 rotatably supported or journalledfor rotation in the base 2 and in a crosspiece disposed between theupstanding parts 3 as shown in FIG. l. In the nonenergized state of therelay the strip-form armature 7 is held by spring means to be describedbelow, in a position in which the longitudinal axis of this armatureforrns a fairly small angle with the plane of the drawing, in such a waythat the left end of the armature is disposed above this plane and theright end below this plane (see FIGURE l).

A cam element l of susbtantially rectangular cross section is positionedbetween armature 7 and base 2 and is rigidly mounted on the shaft S forrotation therewith as shown in FiG. 2. Element 9 is so mounted that inone direction, element 9 is asymmetrical with respect to this shaft 8(sce FiG'URE 2). The element is disposed between and surrounded by thelegs of a double-curved or LJ-shaped leaf spring lo, the bight portionof which engages with and is disposed about an opstanding post 11,provided by base 2 and disposed in an opening in one of the parts 3 asshown in FG. 2. The legs of spring lil bias element 9 for movement tothe position shown in FiG. 2 in which the armature 7 is biased to thenon-energized, non-aligned position described above. The legs of theleaf spring lil are spring biased for movement toward each other andeach of the legs respectively, carry at their free outer ends, anelectrical contact l2, which constitute the movable contacts of therelay. The relay also includes a pair of stationary electrical contactsi3 secured to suitable terminals on base 2 and positioned for engagementwith movable contacts 12 as shown in FIG. 2.

When coil d of the relay is energized by current of a predeterminedvalue the armature 7 will rotate (against the bias of spring itl) insuch a way that the longitudinal axis of the armature '7 comes to lie inthe plane of the drawing in which position the longitudinal axis isaligned with the pole-pieces 6. Armature 7 in rotating from thenon-energized, non-aligned or from the starting position of the armatureshown in FIGURE l, to the energizedu aligned position described above,causes element 9, to rotate counterclockwise from the FIG. 2 position tospread the legs of the leaf spring ill apart and move the contacts 12into Contact with the stationary contacts i3. The asymmetrical positionof the element 9 with .res ect to the axle or shaft 8 (as shown in FIG.2) cornpensates for the .fact that the corner of the element 9 whichmoves the upper leg of the leaf spring i@ (as shwon in FiG. 2) isfarther from the curved end or bight portion of the said spring than thecorner which acts on the lower leg of the leaf spring lil and advantageonsiy assure that both of the movable contacts 12 are displaced bythe same distance from the starting position shown in FIGURE 2.

In order to be able to easily adjust the sensitivity of theabove-described relay, externally of the relay, a coil spring lo' isdisposed on the end of the axle or shaft 3 which extends through thebase 2 into the central bore a, r saves J3 of a projection lli formed onthe base 2. Coil spring l5 is rigidly connected at its inner end, withthe corresponding end of the axle 3, and at its outer end, it isfastened to the inner wall of an adjusting Vscrew lo, which is threadedinto the :threaded central bore of the projection 14. In this way, acontrollable torsion couple can be exerted on Ithe armature axle orshaft 3 for adjusting the sensitivity of the relay.

Finally, for easy and quick mountingiof the relay, there is provided abow or bracket i7 which is provided with mounting holes lil. Each of thelegs 19 of this bracket is provided with an opening, receives andinteriits with correspondingly-shaped projections on the cap l for snapmounting of the bracket on the cap or housing l of the relay.

It is -to be understood that the execution details of the describedrelay may be modified in various manners without thereby departing fromthe framework of the invention.

l claim:

1. An electrical switching device comprising a housing, a coil and apair of pole pieces; an armature disposed within said housingintermediate said pole pieces; sai-d armature being in a magneticcircuit with said coil and pole pieces; shaft means mounting saidarmature for rotation about an axisV Which is substantiallyperpendicular to the longitudinal axis of said coil and 'for rotationbetween a first position in which said armature is aligned with saidpole pieces and a second position in which said armature is out ofalignment with said pole pieces; substantially U-shaped electricallyconductive spring means including a pair of legs interconnected adjacentone end thereof by a bight portion; said shaft means including a memberof substantially rectangular cross section rotatable in response torotation of said armature; said substantially rectangular member beingdisposed intermediate the legs of said electrically conductive U-shapedspring means; said legs boing biased for movement toward each other andinto engagement with said substantially rectangular portion; each ofsaid legs adjacent the other ends thereof carrying an electrical Contactpositioned for engagement with a respective one of a pair of stationaryelectrical contacts mounted within said housing.

2. The switching device as set forth in claim l and wherein saidsubstantially rectangular member is mounted asymmetrically with respectto said shaft means whereby to effect substantially equal displacementof each of said legs of said U-shaped spring means when said rectangularportion rotates in response to rotation of said armature when said coilis energized by current of a predetermined value.`

3. The switching device as set forth in claim 1 and including springmeans connected with said shaft means urging said armature for rotationto said second position.

4. The switching device as set forth in claim 3 and wherein said lastnamed spring means is also connected with an ladjusting screw threadedlyengaged with said rousing and accessible exteriorly of said housing.

5. The switching device Vas set forth in claim 4 and wherein said lastnamed spring means comprises a coil spring.

6. A switch comprising a housing; first and second electrical contactsmounted in said housing, one of which is movable'into and out ofengagement with the other of said contacts; a movable armature;rotatably mounted shaft means mounting said armature for rotation withsaid shaft means in a rst direction for effecting contact engagement andin a second direction opposite to said first direction for effectingcontact disengagement; magnetic means for moving said armature in saidfirst direction at predetermined electrical conditions; cam meansmounted for rotation with said shaft means and armature; means mountingsaid first contact and comprising a resilient spring member biased intoengagement with said cam means whereby rotation of said armature in saidfirst direction causes s id cam means to displace said resilient springmember to effect contact engagement and rotation of said armature insaid second direction results in movement of said resilient springmember' to effect contact disengagement; and biasing meansinterconnected with said shaft means for biasing said armature formovement in said second direction, and said biasing means being movablerelative to said shaft means for adjusting the bias exerted by saidbiasing means on said armature.

7. A switch comprising a housing; tirst and second electrical contactsmounted in said housing, one of which is movable into and out ofengagement with the other of said contacts; a movable armature;rotatably mounted shaft means mounting said armature for rotation withsaid shaft means in first direction for effecting contact engagement andin a second direction opposite to said iirst direction for effectingcontact disengagement; magnetic means for moving said armature in saidfirst direction at predetermined electrical conditions; cam meansmounted for rotation with said shaft means and armature; means mountingsaid first contact and comprising a resilient spring member biased intoengagement with said cam means whereby rotation of said armature in saidfirst direction causes said cam means to displace said resilient springmember to effect contact engagemont and rotation of said armature insaid second direction results in movement of said resilient springmember to effect contact disengagement; biasing means interconnectedwith said shaft means for biasing said armature for novement in saidsecond direction; and adjustable screw means interconnected with saidbiasing means and engaged with and accessible exteriorly of said housingto vary the bias exerted by said biasing means on said armature.

8. A switch comprising a pair of stationary contacts; a pair of movablecontacts positioned for movement into and out of engagement with saidstationary contacts; a substantially U-shaped electrically conductivespring mentber comprising a pair of legs each having a respective one ofsaid movable contacts mounted on one end thereof and a bight portioninterconnecting the other end of each of said legs; cam means having asubstantially rectangular cross section and being disposed intermediatethe legs of said substantially U-shapcd spring means; said legs beingbiased for movement toward each other and into engagement with said cammeans; shaft means mounting said cam means for rotation in a firstdirection for carnming said movable contacts for movement in onedirection relative to said stationary contacts against the bias of saidlegs, and in a second direction for moving said movable contacts in anopposite direction relative to said stationary contacts; and biasingmeans interconnected with said shaft means for biasing said cam meansfor movement in said second direction, said biasing means being movablerelative to said shaftmeans for adjusting the bias exerted by saidbiasing means. v

9. The switch as set forth in claim 8 and wherein said one direction isin a direction toward engagement with said stationary contacts and saidopposite direction is in a direction away from said stationary contacts.

' 10. The switch as set forth in claim 8 and wherein said substantiallyrectangular cam means is mounted asymmetrically with respect to saidshaft means whereby to effect substantially equal displacement of eachof said legs of said U-shaped spring member upon rotation of said cammeans. Y' Y A l1. An electrical switching device comprising a housing;an armature disposed within said housing; magnetic means Vincluding acoil and a pair of pole pieces for causing rotary movement of saidarmature at predetermined electrical conditions; shaft means mountingsaid armature for rotation about an axis which is substantiallyperpendicular to the longitudinal axis of said coil; a substantiallyLlshaped electrically conductive spring member including a pair of legsinterconnected at one end thereof; cam means on said shaft means havinga substantially recrotation of said armature; said cam means beingdisposed intermediate the legs of said spring member; said legs beingbiased for movement toward each other and into engagement with said cammeans; and an electrical contact mounted adjacent the other end of eachof said'legs for engagement with a respective one of la pair ofstationary electrical contacts mounted within said housing.

References Cited in the ile of this patent UNITED STATES PATENTS BossartNov. E, 1932 Zoerlein Aug. 15, 1950 Koenig Jan. 20, 1953 Fitch Feb. 24,1953 Despard Dec. 14, 1954 Zimmer Feb. 18, 1958 Bengtsson et al Mar. 4,1958 Brunicardi Oct. 17, 1961

1. AN ELECTRICAL SWITCHING DEVICE COMPRISING A HOUSING, A COIL AND APAIR OF POLE PIECES; AN ARMATURE DISPOSED WITHIN SAID HOUSINGINTERMEDIATE SAID POLE PIECES; SAID ARMATURE BEING IN A MAGNETIC CIRCUITWITH SAID COIL AND POLE PIECES; SHAFT MEANS MOUNTING SAID ARMATURE FORROTATION ABOUT AN AXIS WHICH IS SUBSTANTIALLY PERPENDICULAR TO THELONGITUDINAL AXIS OF SAID COIL AND FOR ROTATION BETWEEN A FIRST POSITIONIN WHICH SAID ARMATURE IS ALIGNED WITH SAID POLE PIECES AND A SECONDPOSITION IN WHICH SAID ARMATURE IS OUT OF ALIGNMENT WITH SAID POLEPIECES; SUBSTANTIALLY U-SHAPED ELECTRICALLY CONDUCTIVE SPRING MEANSINCLUDING A PAIR OF LEGS INTERCONNECTED ADJACENT ONE END THEREOF BY ABRIGHT PORTION; SAID SHAFT MEANS INCLUDING A MEMBER OF SUBSTANTIALLYRECTANGULAR CROSS